Intervertebral implants and related methods of use

ABSTRACT

A method of implanting an intervertebral spacer may include positioning the intervertebral spacer within an intervertebral space defined by adjacent vertebral bodies. The intervertebral spacer may include a plurality of bores, and each of the plurality of bores may be configured to receive either a linear fastening element or a curvilinear fastening element. The method also may include selecting a first fastening element from a group including linear fastening elements and curvilinear fastening elements, and inserting the first fastening element into a first bore of the plurality of bores such that the first fastening element is inserted into one of the adjacent vertebral bodies to secure the intervertebral spacer within the intervertebral space.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 15/962,174, filed Apr. 25, 2018, which is a continuation ofU.S. patent application Ser. No. 14/476,439, filed Sep. 3, 2014, all ofwhich are herein incorporated by reference in their entirety.

FIELD OF THE INVENTION

Various examples of the present disclosure relate generally to vertebralimplants and related systems and methods. More specifically, the presentdisclosure relates to vertebral anchors, spacers, devices, systems, andmethods for repairing and/or replacing intervertebral discs of apatient.

BACKGROUND

A common procedure for handling pain associated with intervertebraldiscs that have become degenerated due to various factors such as traumaor aging is the use of intervertebral spacers to, e.g., fuse one or moreadjacent vertebral bodies. Generally, to fuse adjacent vertebral bodies,the native intervertebral disc is first partially or fully removed. Anintervertebral spacer is then typically inserted between neighboringvertebral bodies to maintain normal disc spacing and restore spinalstability, thereby facilitating an intervertebral fusion.

There are a number of known conventional intervertebral spacers andmethodologies in the art for accomplishing the vertebral fusion. Theseinclude screw and rod arrangements, solid bone implants, andintervertebral spacers which include a cage or other implant mechanismthat may be packed with bone and/or bone growth inducing substances.These devices may be implanted between adjacent vertebral bodies inorder to fuse the vertebral bodies together, potentially alleviating anyassociated pain.

However, there are drawbacks associated with the known conventionalvertebral spacers and methodologies. Some conventional vertebral spacersmay not be optimally configured for insertion into irregular or curvedportions of the spine. For example, at the most caudal or most cephaladcervical disc spaces or caudal lumbar levels, conventional, angledinstruments used to install conventional fasteners may interfere withthe chin, chest, or other portion of a patient's anatomy, makinginsertion of conventional fastening members difficult.

SUMMARY OF THE DISCLOSURE

The present disclosure relates to examples of intervertebral spacers andrelated methods of use. A method of implanting an intervertebral spacermay include positioning the intervertebral spacer within anintervertebral space defined by adjacent vertebral bodies. Theintervertebral spacer may include a plurality of bores, and each of theplurality of bores may be configured to receive either a linearfastening element or a curvilinear fastening element.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various exemplary embodiments andtogether with the description, serve to explain the principles of thedisclosed examples.

FIGS. 1-8 illustrate various views of a vertebral spacer in accordancewith a first exemplary embodiment of the present disclosure.

FIG. 9 is a perspective view of another exemplary intervertebral spacerin accordance with an example of the present disclosure.

FIG. 10 is an insertion device in accordance with an example of thepresent disclosure.

FIGS. 11-14 depict various end or cross-sectional views of the insertiondevice of FIG. 10.

FIGS. 15-17 depict the insertion device of FIG. 10 coupled with anintervertebral anchor in accordance with an example of the presentdisclosure.

FIGS. 18-23 depict an exemplary tool and method of installing avertebral anchor in accordance with an example of the presentdisclosure.

FIG. 24 is a perspective view of another exemplary insertion device inaccordance with an example of the present disclosure.

FIG. 25 is a perspective view of an insertion device and anintervertebral spacer having a plurality of fasteners in accordance withan example of the present disclosure.

FIGS. 26-28 depict another exemplary method of installing a vertebralanchor in accordance with an example of the present disclosure.

FIG. 29 is a side view of a vertebral anchor in accordance with anexample of the present disclosure.

FIG. 30 is an enlarged view of detail A in FIG. 29, illustrating adistal portion of the vertebral anchor of FIG. 29.

FIG. 31 is a top view of the vertebral anchor of FIG. 29.

FIG. 32 is an enlarged view of detail B in FIG. 31, illustrating adistal portion of the vertebral anchor of FIG. 31.

FIG. 33 is a perspective view of the vertebral anchor of FIG. 29.

FIG. 34 is an enlarged view of detail C in FIG. 33, illustrating adistal portion of the vertebral anchor of FIG. 33.

FIG. 35 is another perspective view of the vertebral anchor of FIG. 29.

FIG. 36 is an end view of the vertebral anchor of FIG. 29.

FIGS. 37-40 illustrate various views of another exemplary vertebralanchor in accordance with an example of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIGS. 1-8 illustrate the different views of an intervertebral spacer 10according to the present disclosure. The intervertebral spacer 10 asshown in FIGS. 1-8 may be, e.g., a stand-alone anterior lumbar interbodyspacer used to provide structural stability in skeletally matureindividuals following discectomies. These intervertebral spacers may beavailable in various heights and geometric configurations to fit theanatomically needs of a wide variety of patients. Specifically, FIGS.1-8 illustrate one embodiment of an intervertebral spacer 10.Intervertebral spacer 10 may be generally positioned in theintervertebral space between two adjacent vertebral bodies. As shown inthe figures, intervertebral spacer 10 may include a spacer portion 12and a plate portion 14. In one example, the spacer portion 12 mayinclude a graft window 11 for the placement of, e.g., bone graft orbone-growth inducing material, to enhance fusion between two adjacentvertebral bodies.

The spacer portion 12 can be comprised of any material that is conduciveto the enhancement of fusion between the two adjacent vertebral bodies.In one particular embodiment, the spacer portion 12 is made of PEEKmaterial, which may be physiologically compatible. It should be notedthat any other materials that are physiologically compatible also may beused. The spacer portion 12 may include tantalum pins that enableradiographic visualization, or other suitable radiographic markers. Thespacer portion 12 further may include superior and inferior surfacesthat are provided with a plurality of geometric configurations, such as,e.g., protrusions 13 (e.g., ribs, bumps, other textures, or the like).The superior and inferior surfaces of the spacer portion 12 may bebi-convex for greater contact with the vertebral endplates of theadjacent vertebral bodies. The protrusions 13 can be configured to beany size or shape for further anchoring the spacer portion 12 to each ofthe adjacent vertebral bodies. Protrusions 13 on the superior andinferior surfaces of each implant may grip the endplates of the adjacentvertebral bodies to aid in expulsion resistance.

The plate portion 14 can also be comprised of any physiologicallycompatible material. In one example, the plate portion 14 of theintervertebral spacer 10 may be formed from titanium. The plate portion14 may include at least one bore 26. In some embodiments, plate portion14 may include a plurality of bores 26, in such embodiments, one or morebores 26 may or may not include threads for receiving correspondingthreads on a fastener. That is to say, in some examples, one or more ofbores 26 may interact with features (e.g., threads) configured toreceive features (e.g., corresponding threads) of a fastening member(e.g., a linear bone screw) to be disposed therethrough. Bores 26 may besubstantially linear. Such a configuration allows bores 26 to receiveboth linear fastening members and curvilinear fastening members. Thatis, a given bore 26 may be configured to receive either a linearfastening member (e.g., a screw) or a curvilinear fastening member (asdiscussed below in greater detail) at the discretion of an operator,surgeon, physician, or the like. In one embodiment, e.g., bores 26 mayinclude one or more features, e.g., threads, that are configured toengage with threads of a fastening member (e.g., a linear fasteningmember or bone screw). Further, in some examples, a curvilinearfastening member disposed through a given bore 26 may be configured soas not to engage the threads of the given bore 26. Still further, eachbore 26 may include locking features configured to engage withcomplimentary features on a curvilinear fastening member to prevent thecurvilinear fastening member from rotating when disposed through thebore 26. In one example, each bore 26 may be defined by acircumferential wall having a recess (not shown) disposed therein. Therecess may be configured to receive a protrusion extending from thecurvilinear fastening member to prevent the curvilinear fastening memberfrom rotating. In one example, three bores 26 may be provided. In yetanother example, two outer bores 26 may surround a central bore 26. Thetwo outer bores 26 may be angled to guide a fastening member (e.g., avertebral anchor 300 described with reference to FIGS. 29-36, or a bonescrew) along a first trajectory 40 shown in FIG. 14 (e.g., toward one ofa superior or inferior surface of intervertebral spacer 10), while thecentral bore 26 may be angled to guide a fastening member along a secondtrajectory 42 (e.g., toward the other of the superior and inferiorsurface of intervertebral spacer 10), and vice versa. In some examples,all bores 26 may guide respective fasteners along the same trajectory.The bores 26 can accommodate a straight longitudinal fastening member(e.g., a screw, pin, or the like) and/or a fastening member exhibiting acurvature (e.g., vertebral anchor 300 shown in FIGS. 1-8). In someexamples, a combination of vertebral anchors 300 and conventional screwsmay be used to install the same intervertebral spacer 10.

Also, in the plate portion 14 of the intervertebral spacer 10, afastener back out prevention mechanism may be provided. The fastenerback out prevention mechanism may include one or more screws 16, eachhaving a head portion 24 and a shank 22 having threads 22 a. Shank 22may be received by a bore 48 (shown in FIG. 8) that extends from a firstside 44 of plate portion 14 toward a second side 46 of plate portion 14.Shank 22 also may be received by a nut 18 having a threaded bore 18 a(shown in FIG. 1). Nut 18 may have a substantially rectangularcross-section, or may have another suitable shape. Nut 18 may be securedwithin a recess 20 on second side 46 of plate portion 14. However, it iscontemplated that screws 16 may be secured to plate portion 14 by anyother suitable mechanism. Head portion 24 may have a generallyrectangular cross-section such that it may prevent a fastening memberfrom backing out of bores 26 when disposed in certain configurations(e.g., a blocking configuration). For example, referring to FIG. 8, thehead portion 24 of screw 16 may extend over, cover, and/or block atleast a portion of the opening of one more of bores 26, preventing afastening member (e.g., a vertebral anchor 300 or a bone screw) extendedthrough a bore 26 from backing out of plate portion 14 and a vertebralbody. It is also contemplated that in some examples, a single headportion 24 may extend at least partially over two adjacent bores 26(e.g., both an outer bore 26 and a central bore 26), thereby blockingthe openings of more than one bore 26 at the same time while disposed ina blocking configuration. Head portion 24 can be moved from the blockingconfiguration to a non-blocking configuration by rotating head portionby, e.g., 90 degrees or another suitable measure. While depicted asrectangular, it is contemplated that head portion 24 may be formed inother suitable elongate shapes, such as, e.g., cylindrical or the like.In the example of FIG. 8, plate portion 14 may be configured to receivetwo screws 16 in bores 48 (shown in FIG. 8). Each of the screws 16 maybe configured to block fastening members disposed in an outer bore 26and a central bore 26, such that each outer bore 26 is blocked by asingle screw 16, and the central bore 26 is blocked by both screws 16.

A coupling mechanism may connect the spacer portion 12 and the plateportion 14 rigidly to each other, if desired. With reference to FIG. 2,the coupling mechanism may include one or more fastening members 34 thatextend through corresponding recesses 36 disposed through spacer portion12 and recesses 38 disposed through at least a portion of plate portion14. In one example, a fastening member 26 may extend through thesuperior and inferior surfaces of spacer portion 12 (via a recess 36)and may be received by recess 38 of plate portion 14, thereby couplingspacer portion 12 and plate portion 14. It is contemplated that recess38 and fastening member 26 may include complimentary mating features(e.g., threads) to facilitate coupling of plate portion 14 to spacerportion 12. In the example shown in FIG. 2, plate portion 14 may beformed by three bore sections 28, 30, and 32. Bore sections 28, 30, and32 may either be integrally formed or detachable with spacer portion 12.In one example, bore section 28 may be integral with spacer portion 12while bore sections 30 and 32 may be detachable with spacer portion 12via fastening members 34 and recesses 36 and 38. In one example, thedetachable bore sections 30 and 32 may include the outer bores 26 thatare configured to direct a vertebral anchor 300 or bone screw along thefirst exit trajectory 40, and the bore section 28 may include thecentral bore 26 configured to direct a vertebral anchor 300 or bonescrew along the second exit trajectory 42. Further, one or more of thebore sections 28, 30, and 32 may include a portion configured to extendthrough a slot of or other opening in spacer portion 12. In suchexamples, the recesses 36, 38, or the like associated with the boresections may align with recesses formed through spacer portion 12 toreceive fastening members 34.

Plate portion 14 also may include coupling features for coupling plateportion 14 to an anchor insertion device 100 which will be describedfurther with reference to FIGS. 10-23. As shown in FIG. 8, plate portion14 may include a channel (e.g., a snap-fit channel) 50 having an openingdisposed in an outer surface of plate portion 14. The channel 50 may beconfigured to receive an extension (e.g., a cantilever and/orsnap-fitting extension) of anchor insertion device 100 to couple plateportion 14 to the insertion device 100. In some examples, channel 50 maybe disposed in bore section 30 of plate portion 14. With continuingreference to FIG. 8, channel 50 may have a generally ovular opening,although other suitable opening configurations such as, e.g., circular,square, rectangular, star-shaped, or the like are also contemplated.Plate portion 14 also may include a bore 52 (e.g., a threaded bore)having an opening that is also disposed through an outer surface ofplate portion 14. In one example, bore 52 may be disposed through boresection 32 of plate portion 14.

In an exemplary method, a physician, surgeon, or other suitable operatormay remove, among other things, the native intervertebral disc betweentwo vertebral bodies. The operator then may select a givenintervertebral spacer, e.g., intervertebral spacer 10, to replace theremoved native intervertebral disc. Based on the geometry of thesurrounding vertebral bodies and/or anatomy, the operator may determinethat linear fastening members (e.g., linear bone screws), curvilinearfastening members (e.g., vertebral anchors 300 or 400), or a combinationof linear fastening members and curvilinear fastening members, willprovide optimal fit and securement of intervertebral spacer 10 betweenthe vertebral bodies. For example, the curvature of the spine at one ormore of the vertebral bodies may substantially inhibit the use of thetools and driving members used to install linear fastening members. Insuch examples, curvilinear fastening members may be selected to secureintervertebral spacer 10. The curvilinear fastening members may beinstalled through the same linear bore 26 that may be configured toreceive linear fastening members. Further, the curvilinear fasteningmembers may be installed through the linear bore with a positioningmember (described with reference to FIG. 10) utilizing a guide memberthat can be extended only along a linear track.

In one example, one or more curvilinear fasteners may be used to secureintervertebral spacer 10 to one vertebral body defining anintervertebral space, while one or more linear fasteners may be used tosecure intervertebral spacer 10 to the other vertebral body defining theintervertebral space. For example, curvilinear fasteners may be extendedthrough outer bores 26 while a linear fastener is extended throughcentral bore 26. Alternatively, linear fastening members may be extendedthrough outer bores 26 while a curvilinear fastening member is extendedthrough central bore 26. In yet another example, both linear andcurvilinear fastening members may be used to secure the sameintervertebral spacer into a given vertebral body. That is, acurvilinear fastening member may be extended through one outer bore 26,while a linear fastening member is extended through the other outer bore26.

FIG. 9 depicts an intervertebral spacer 90 in accordance with an exampleof the present disclosure. In some examples, intervertebral spacer 90may be substantially similar to intervertebral spacer 10, or may beanother suitable intervertebral spacer. In the example shown in FIG. 9,spacer 90 may be a generally rectangular spacer defining a cavity 91.Cavity 91 may be packed with bone graft or bone-growth inducingmaterials. Spacer 90 may include one or more of inferior surfaces,superior surfaces, biconvex surfaces, among others. In some examples,the surfaces of spacer 90 or any other bone contacting surface describedin the present disclosure may include one or more of teeth, ridges,friction increasing elements, keels, or gripping or purchasingprojections.

Spacer 90 may include a plate portion 92 that may include one or morefeatures described with reference to plate portion 14 of intervertebralspacer 10. In one example, one or more bores 93 may disposed throughplate portion 92. Though FIG. 9 depicts two bores 93, those of ordinaryskill in the art will recognize that any suitable number of bores may beprovided. Bores 93 may include one or more features described withreference to bores 26 of intervertebral spacer 10. The two bores 93 maybe angled to guide a fastening member (e.g., a vertebral anchor 300 or abone screw) along differing trajectories. For example, one bore 93 maybe angled to urge a fastening member along a first trajectory (e.g.,toward one of a superior or inferior surface of intervertebral spacer90), while the other bore 93 may be angled to urge a fastening memberalong a second trajectory (e.g., toward the other of the superior andinferior surface of intervertebral spacer 90). The bores 93 canaccommodate a straight longitudinal fastening member (e.g., a screw,pin, or the like) and/or a fastening member exhibiting a curvature(e.g., vertebral anchor 300 or 400). In some examples, a combination ofvertebral anchors 300 or 400 and conventional screws may be used toinstall the same intervertebral spacer 90 as shown in FIG. 25. Acircumferential wall defining bores 93 may further include one or morerecesses 94 disposed therein. The one or more recesses 94 may beconfigured to receive one or more protrusions 460 disposed on a headportion 406 of a vertebral anchor 400 (described with reference to FIGS.37-40). Thus, in some examples, recesses 94 may be partially-sphericalto receive protrusions 460. However, it is contemplated that recesses 94may be formed in any suitable shape configured to receive protrusions460. Plate portion 92 also may include a bore 95 having an opening thatis disposed through an outer surface of plate portion 92. The bore 95may include one or more features, e.g., threads or other features toengage with an insertion device 200 described with further detail below.Intervertebral spacer 90 also may include one or more featuresconfigured to prevent fastening members from backing out of bores 93,such as, e.g., screws 16 described with reference to FIGS. 1-8.

Intervertebral spacer 90 may be inserted into an intervertebral spacebetween two vertebral bodies in a substantially similar manner asintervertebral spacers 10. In one example, one or more curvilinearfasteners may be used to secure intervertebral spacer 90 to onevertebral body defining an intervertebral space, while one or morelinear fasteners may be used to secure intervertebral spacer 90 to theother vertebral body defining the intervertebral space. For example, acurvilinear fastener may be extended through one bore 93 while a linearfastener is extended through the other bore 93.

An insertion device 100 is shown in FIG. 10, which may be used toposition vertebral anchors 300 through a plate portion of anintervertebral spacer (e.g., plate portion 14 of intervertebral spacer10) and through a vertebral body. Insertion device 100 may extend from atrailing end 102 toward a leading end 104. A trailing housing 106 may bedisposed at trailing end 102 and may define one or more elongatechannels 108. In the embodiment shown, three elongate channels 108 areshown, although any other suitable number of elongate channels 108 maybe disposed through trailing housing 106. Each of elongate channels 108may receive a guide member 110 therethrough. Guide member 110 mayinclude a head portion 112 and an elongate portion 114 that extends awayfrom the head portion 112. In some examples, head portion 112 mayinclude one or more flattened and reinforced surfaces configured toreceive the force of a striking member (e.g., a hammer or the like).Elongate portion 114 may be extended through one or more elongatechannels 108 toward leading end 104. The distal or leading end ofelongate portion 114 may include a stepped portion 132 (shown in FIG.18). Stepped portion 132 may be separated from the remainder of elongateportion 114 by a vertical wall 130. In some examples, stepped portion132 may include a smaller cross-sectional dimension (e.g., thickness orwidth) as compared to a remainder of elongate portion 114.

A connecting housing 115 may extend from trailing housing 106 toward ananchor housing 116 disposed at leading end 104. In some examples,connecting housing 115 may be an alignment shaft configured to alignelongate channels 108 with a corresponding number of anchor channels 118(see FIG. 11) disposed in anchor housing 116. In the embodiment shown inFIG. 10, connecting housing 115 may extend from only one of elongatechannels 108 to couple trailing housing 106 to anchor housing 116.However, those of ordinary skill in the art will appreciate that a shaft116 may extend from more than one elongate channel 108 toward anchorhousing 116. Guide member 110 may extend through an elongate channel108, through connecting housing 115, and into an anchor channel 118,where it may come into contact with a vertebral anchor 300 just beforeinserting the vertebral anchor 300 through a vertebral body, asdescribed further with reference to FIGS. 18-23. In some examples,connecting housing 115 may merely align certain elongate channels 108 intrailing housing 106 with anchor channels 118 disposed in anchor housing116. In such examples, elongate portion 114 of guide member 110 may exita leading end of elongate channel 108 and extend through an open andunconfined space before entering a trailing end of an anchor channel118.

As best seen in FIG. 11, anchor housing 116 may include one or moreanchor channels 118. Each anchor channel 118 may have a variablecross-section along the length of anchor housing 116. In some examples,a given cross-section of anchor channel 118 may be t-shaped or anyanother suitable cross-section. A curvature at the leading end of anchorchannel 118 may be complimentary to certain portions of a curvilinearanchor (e.g., anchor 300 shown in FIG. 29). Those portions may includean elongate shank 308 and elongate fin 310, shown in FIGS. 29 and 31.That is, anchor channel 118 may be defined by a concave surface 119 thatis complimentary to elongate shank 308 of vertebral anchor 300. Forexample, a laterally extending portion 148 of each channel 118 may beconfigured to complement and receive a curved elongate shank 308, and avertically extending portion 126 of each channel 118 may receive acurved elongate fin 310. Thus, a vertebral anchor 300 may be disposedwithin each anchor channel 118 and may exit anchor channel 118 along agiven exit trajectory. Some anchor channels 118 may urge a vertebralanchor 300 along a first exit trajectory 120 while other exit channels118 may urge a vertebral anchor 300 along a second exit trajectory 122.First exit trajectory 120 may extend in a first vertical direction outof the leading end of anchor housing 116 while the second, differentexit trajectory 122 may extend in a second vertical direction out of thetrailing end of anchor housing 116. A given anchor housing 116 mayinclude a plurality of anchor channels 118 that may direct all vertebralanchors 300 along the first exit trajectory 120, all vertebral anchors300 along the second exit trajectory 122, or some vertebral anchors 300along the first exit trajectory 120 and some vertebral anchors 300 alongthe second exit trajectory 122. Each of first and second trajectories120 and 122 may intersect a longitudinal axis of insertion device 100and/or guide member 110. In one example, laterally adjacent anchorchannels 118 may be configured to direct vertebral anchors 300 alongdifferent exit trajectories. In the exemplary embodiment shown in FIGS.11-14, anchor housing 116 may include three anchor channels 118. Twoouter anchor channels 118 may be laterally offset from an inner anchorchannel 118. The outer anchor channels 118 may urge respective vertebralanchors 300 along first exit trajectory 120 while the inner anchorchannel 118 may urge a vertebral anchor 300 along second exit trajectory122. Anchor channel 118 may further include a stop wall 146 (shown inFIGS. 18-23) that may extend radially inward from a wall of anchorchannel 118. Stop wall 146 may be configured to abut a vertical wall ofelongate portion 114 (of guide member 110) to prevent elongate portion114 from being inserted too far distally into a patient by an operator.Thus, stop wall 146 also may prevent an inadvertent excessive force frombeing applied to intervertebral spacer 10 or to a vertebral body byelongate portion 114.

Anchor housing 116 may include one or more features to engage withcorresponding features disposed on plate portion 14 of intervertebralspacer 10. In one example, an extension 117 (e.g., a cantileveredsnap-fit extension 117) may extend longitudinally outward from theleading end (e.g., a distal face) of anchor housing 116. Extension 117may include one or more surfaces configured to engage channel 50 ofplate portion 14 in a snap fit or other suitable engagement. Anchorhousing 116 also may include a threaded shank 113 that extendslongitudinally outward from the leading endface of anchor housing 116.In some examples, threaded shank 113 may be received by bore 52 of plateportion 14. While snap-fit and threaded connections are disclosed in theexamples shown by the figures, it should be noted that any otheradditional or alternative type of engagement may be utilized to coupleanchor housing 116 to plate portion 14.

Anchor housing 116 also may include one or more positioning members 138,as shown in FIG. 18. Each positioning member 138 may secure a vertebralanchor 300 within a respective anchor channel 118. Thus, each anchorchannel 138 may be associated with its own respective positioning member118. In one example, positioning member 138 may be an elongatecantilever that is coupled to a leading end portion of anchor housing116 via a linkage or hinge 140. In some examples, linkage or hinge 140may be a spring-biased linkage or may be another suitable hinge orlinkage. Positioning member 138 may extend from linkage 140 towardtrailing end 102. At its proximal or trailing end, positioning member138 may include a ramp 142 and an extension 144 spaced from ramp 142 bya recess. Ramp 142 may be an inclined surface configured to engageelongate portion 114 of guide member 110. Positioning member 138 may beconfigured to pivot about the linkage 140 and away from an interior ofanchor channel 118 when ramp 142 is engaged by elongate portion 114 ofguide member 110. In some examples, positioning member 138 may pivot ina direction that is opposite to the exit trajectory of its associatedanchor channel 118. That is, if a given anchor channel 118 is configuredto guide a vertebral anchor into a vertebral body along first trajectory120, the associated positioning member 138 of that elongate channel maypivot about linkage 140 in the vertical direction that is opposite tothe vertical vector of first trajectory 120. On the other hand, if agiven anchor channel 118 is configured to guide a vertebral anchor 300along the second trajectory 122, the associated positioning member 138of that anchor channel 118 may be configured to pivot in a verticaldirection that is opposite to the vertical vector of second trajectory122. Extension 144 may include any suitable configuration (e.g., a ballor the like), and may be configured to be releasably coupled to avertebral anchor 300 via groove 318.

Vertebral anchors 300 may be loaded into anchor channels 118 prior tothe coupling of anchor housing 116 to plate portion 14 of intervertebralspacer 10. Vertebral anchors 300 may be loaded from either the trailingend or the leading end of anchor housing 116, if desired. In someexamples, vertebral anchors 300 may be loaded by a spring-loaded blockdevice. In one example, a vertebral anchor 300 may be loaded into theleading end of anchor housing 116 with trailing end 302 of the vertebralanchor being inserted first. That is, trailing end 302 of vertebralanchor 300 may be loaded into anchor channels 118 before leading end304. Thus, vertebral anchors 300 may be loaded in a reverse manner suchthat the vertebral anchors 300 are loaded in the opposite direction towhich they are inserted into the body. As vertebral anchors 300 aremoved proximally through anchor channels 116, groove 318 may be coupledto extension 144 of positioning member 138. The docking, mating, orconnection of extension 144 with groove 318 may fix vertebral anchor 300within anchor channel 118 until vertebral anchor 300 is inserted througha vertebral body. In one example, extension 144 may be a ball and agroove 318 of vertebral anchor 300 may be a socket such that extension144 and groove 318 form a ball and socket joint. However, those ofordinary skill in the art will appreciate that any other suitable formof releasable connection may be utilized.

Anchor housing 116 may be coupled to intervertebral spacer 10 to installvertebral anchors 300 into the body. Anchor housing 116 and plateportion 14 may be aligned via extension 117 and channel 50, and/or viashank 113 and bore 52 in such a manner as to align channels 118 ofanchor housing 116 with bores 26 of plate portion 14. The alignment ofchannels 118 and bores 26 may permit one or more vertebral anchors 300to be guided from a channel 118 through a corresponding bore 26 of plateportion 14, and into a vertebral body. Further, the anchor housing 116and plate portion 14 may be aligned such that the exit trajectory of agiven channel 118 may be aligned (e.g., collinear or coplanar) with theexit trajectory of an aligned bore 26. In some examples, the number ofchannels 118 disposed in anchor housing 116 may correspond exactly withthe number of bores 26. However, it is contemplated that an exactcorrespondence may not exist between channels 118 and bores 26. Forexample, an anchor housing 116 may include fewer channels 118 than bores26 in a plate portion. In such examples, anchor housing 116 may becoupled to plate portion 14 in a number of different configurations. Insuch examples, after a vertebral anchor 300 is inserted through avertebral body, anchor housing 116 may be uncoupled from plate portion14, reloaded with a new vertebral anchor 300, and recoupled to plateportion 14 at a different location.

With continuing reference to FIGS. 18-23, there is depicted an exemplarymethod of positioning a vertebral anchor 300 via insertion device 100.Referring to FIG. 18, vertebral anchor 300 is shown loaded into ananchor channel 118. The vertebral anchor 300 may be secured within theanchor channel 118 via the coupling of extension 144 with groove 318 ofthe vertebral anchor 300 as set forth above. Elongate portion 114 ofguide member 110 then may be advanced distally (e.g., in the directionof leading end 304) such that the distal end of elongate portion 114 maycontact ramp 142 (FIGS. 19 and 20). In some examples, stepped portion132 of elongate portion 114 may contact the ramp 142. Elongate portion114 may be advanced further distally, causing ramp 142 to slidevertically upward, thereby disengaging extension 144 from groove 318 ofvertebral anchor 300 (FIG. 20). As elongate portion 114 is advancedfurther distally, the distal end of elongate portion 114 may abut thetrailing end 302 of vertebral anchor (FIG. 21). In some examples, thestepped portion 132 of elongate portion 114 may abut head portion 306 ofvertebral anchor 300. Uncoupled from extension 144, vertebral anchor 300then may be advanced out of the leading end of anchor housing 116 andanchor channel 118 (FIG. 22) and ultimately inserted into a vertebralbody (not shown) along a given exit trajectory (e.g., trajectory 120 or122.), as shown in FIG. 23. After impacting one vertebral anchor 300through a vertebral body, the same guide member 110 (and elongateportion 114) may be withdrawn and reinserted through a differentelongate channel 108 and anchor channel 118 (having another preloadedvertebral anchor 300), to impact a different vertebral anchor 300, ifdesired. Alternatively, each set of elongate channels may include adedicated guide member 110.

One embodiment of an insertion device 200 is shown in FIGS. 24-28.Insertion device 200 may extend from a first, trailing end 202 toward asecond, leading end 204. A base portion 206 may include a proximalannular rim 208 and base shaft 209 extending therefrom. An alignmentshaft 210 may extend from base shaft 209. In the example shown in FIG.24 the leading end 204 of alignment shaft 210 may have a smallerdiameter than the trailing end of alignment shaft 210, although othersuitable configurations, including a substantially constant diametershaft 210, are also contemplated. In some examples, alignment shaft 210may include one or more longitudinally extending windows 218. In someexamples, alignment shaft 210 may be a hollow elongate shaftaccommodating a drive mechanism 216 therein. Drive mechanism 216 may beconfigured to actuate a coupling 222 disposed at the leading end ofalignment shaft 210. Drive mechanism 216 may be a spring loaded driveshaft configured to reciprocally move coupling 222 between a retractedconfiguration and an extended configuration. While in the extendedconfiguration, coupling 222 may engage with, e.g., bore 95 ofintervertebral spacer 90 to couple insertion device 200 tointervertebral spacer 90. While coupling 222 is engaged to bore 95,drive mechanism 216 may move coupling 222 to the retracted configurationto disengage insertion device 200 from intervertebral spacer 90.

Coupling 222 may be disposed in an anchor housing 220 that is disposedat the leading end 204 of alignment shaft 210. Anchor housing 220 mayinclude at least one anchor channel 224. Anchor channel 224 may includeone or more features described with reference to anchor channel 118 ofinsertion device 100. For example, anchor channel 224 may have avariable cross-section along its length and may have a concave surface230 (shown in FIGS. 26-28) that is complimentary to, e.g., elongateshank 408 of spacer 400 shown in FIG. 37. For example, a laterallyextending portion of anchor channel 224 may receive a curved elongateshank 408. A guide member 228 that may be substantially similar to guidemember 110 may be inserted through anchor channel 224 to assist withdeploying an anchor disposed therein.

It is contemplated that insertion device 200 may include additional oralternative features for attaching to intervertebral spacer 90 such as,e.g., positive attachments, cam attachments, threaded attachments orother suitable attachments. In some examples, pins or other members alsomay prevent the rotation of insertion device 200 relative tointervertebral spacer 90 when the insertion device 200 andintervertebral spacer 90 are engaged. In some examples, the leading endof insertion device 200 may couple to the anterior face, lateral sides,or other regions of intervertebral spacer 90. In one embodiment, theinsertion device 200 may include a stop that extends in either thecephalad or caudal direction of a centerline of insertion device 200 toprevent the intervertebral spacer 90 from being inadvertently impactedundesirably. That is, a stop may extend from the superior or inferiorsurface of insertion device 200 and may contact, e.g., a surface of theintervertebral spacer or vertebral body.

Anchor housing 220 may be coupled to an intervertebral spacer, e.g.,intervertebral spacer 90, to install vertebral anchors 400 into thebody. Anchor housing 220 and plate portion 92 may be aligned viacoupling 222 and bore 95, in such a manner as to align channel 224 ofanchor housing 220 with a bore 93 of plate portion 14. In some examples,anchor channels 224 may be laterally offset from the length of alignmentshaft 210. The alignment of channel 224 and bore 93 may permit one ormore vertebral anchors 400 to be guided from a channel 224 through acorresponding bore 93 of plate portion 92, and into a vertebral body.Further, the anchor housing 220 and plate portion 92 may be aligned suchthat the exit trajectory of a given channel 224 may be inline (e.g.,collinear or coplanar) with the exit trajectory of an aligned bore 93.While only one anchor channel 224 is shown in the example of FIGS.24-28, it is contemplated that additional anchor channels 224 may beutilized (e.g., a double or multi-barreled configuration) such that thenumber of channels 224 disposed in anchor housing 220 may correspondexactly with the number of bores 93 in vertebral spacer 90. In someexamples, a guide member may extend through one or more anchor channels224 to simultaneously insert one or more fastening members (e.g.,vertebral anchors or screws) through one or more vertebral bodies. Othermechanisms of anchor insertion are also contemplated such as, e.g., ablocking set screw or leaf spring cutout of the spacer or plate that isflexible in the insertion direction and stiff in the expulsiondirection. An associated intervertebral spacer also may includerotational stabilizers to add stability to the construct in vivo, andmay contain radiographic markers to aid in interoperative visibility.

FIGS. 26-28 depict an exemplary method of positioning a vertebral anchor400 via insertion device 200. Referring to FIG. 26, vertebral anchor 400is shown loaded into an anchor channel 224. The vertebral anchor 400 maybe secured within the anchor channel 224 by any suitable mechanism.Guide member 228 then may be advanced distally such that the distal endof guide member 228 may contact head portion 406 of vertebral anchor 400(FIG. 26). Guide member 228 may extend from trailing end 202, through atrailing opening 226 (shown in FIG. 25) of anchor channel 224 to abut avertebral anchor 400. Vertebral anchor 400 then may be advanced out ofthe leading end of anchor housing 220 and anchor channel 224 (FIG. 27)and ultimately inserted into a vertebral body (not shown) along a givenexit trajectory, as shown in FIG. 28. After impacting one vertebralanchor 400 through a vertebral body, anchor housing 220 may bedisengaged from plate portion 92, and another vertebral anchor 400 maybe loaded into anchor channel 224. When anchor channel 224 is reloaded,anchor housing 220 may be re-engaged with plate portion 92 in asubstantially similar manner as before, except that anchor channel 224may be aligned with a different bore 93 of vertebral spacer 90.

A vertebral anchor 300 shown in FIG. 29 may extend from a first,trailing end 302 toward a second, leading end 304, and may include ahead portion 306, an elongate shank 308, and an elongate fin 310.Vertebral anchor 300 may be formed from a rigid, bio-compatible materialsuch as, e.g., titanium or polyetheretherketone (PEEK), among others.The head portion 306, elongate shank 308, and elongate fin 310 may beformed of the same or of different materials. Portions of vertebralanchor 300 may be treated with a titanium and/or hydroxyapatite plasmaspray coating to encourage bony on-growth, improving the strength andstability of the connection between the respective component and theunderlying bone (e.g., a vertebral body). Any other suitable coatingalso may be provided on one or more surfaces of vertebral anchor 300.Such coatings may include therapeutic agents (e.g., antibioticcoatings), if desired. Vertebral anchor 300 also may include radiopaquemarkings to facilitate in vivo visualization and insertion. Vertebralanchor 300 may be configured to be impacted into vertebral bodies tosecure implants within the intervertebral space of a patient. Vertebralanchor 300 may be inserted into the patient and impacted through thebone of a vertebral body.

The head portion 306 may be disposed at trailing end 302 of vertebralanchor 300 and may be generally spherical or ball shaped. In someexamples, the head portion 306 may be shaped in a substantially similarmanner as the head portion of other vertebral fastening members (e.g.,bone screws). In some examples, the head portion 306 may include a bore312 to facilitate removal of vertebral anchor 300 from a vertebral body.In some examples, bore 312 may be a threaded bore or may include othersuitable features to facilitate the extraction of vertebral anchor 300from a vertebral body by, e.g., a pulling tool or the like. In someexamples, a tool with a threaded tip may be rotated to threadinglyengage bore 312, and the tool may be linearly withdrawn to extractvertebral anchor 300 from within a vertebral body. The pooling tool alsomay include one or more of a cam attachment, an expandable driver, oranother feature for removing vertebral anchor 300. A plurality of slotsor notches 314 may be formed in the outer periphery of head portion 306.In some examples, a plurality of flanges 316 may define the plurality ofslots 314 about the outer periphery of the head portion 306. The flanges316 may be disposed around head portion 306 to form a generally t-shapedcross-section. A groove 318 (e.g., a semi-cylindrical groove) may beformed in the outer periphery of head portion 306. In some examples, thegroove 318 may be disposed within one of the flanges 316, or in anothersuitable location on head portion 306. In some examples, one or moregrooves 318 may be disposed along the periphery of head portion 306.Groove 318 may cooperate with an extension (e.g., extension 144 shown inFIG. 18) of an installation device as discussed above. In some examples,the flanges 316 and slots 314 of the head portion 306 may cooperate withor be received by complimentary shaped features in a spacer, implant,plate system or the like. The interaction between the flanges 316, slots314, and the complimentary-shaped features may prevent the relativerotation of vertebral anchor 300 before, during and/or afterinstallation of vertebral anchor 300 into a vertebral body.

Elongate shank 308 may extend away from the head portion 306 toward theleading end 304. In some examples, elongate shank 308 may be planar andmay exhibit a curvature as it extends away from the head portion 306.That is to say, in some examples, elongate shank 308 may include acurvilinear configuration. Specifically, elongate shank 308 may becurved (e.g., symmetrically curved) about a longitudinal axis. Morespecifically, elongate shank 308 exhibit a curvature about a medianlongitudinal axis. Further, the elongate shank 308 may be curved suchthat a concave surface 320 and a convex surface 322 extend from trailingend 302 toward leading end 304. The leading end of the elongate shank308 may be formed by a pair of inclined surfaces 323 and 324 that extendfrom the lateral ends of elongate shank 308 toward an apex 326. Apex 326may be disposed on a longitudinal axis of vertebral anchor 300. Thus, atleading end 304, elongate shank 308 may be formed as a projectile point,arrowhead, bladed edge, cutting edge, or the like to facilitateimpaction and insertion through bone and/or tissue. To reduce impactionforce, the apex 326 may feature a hollow style which may be similar to aknife edge. That is, the edge or apex 326 of the anchor may approach ashallow angle, e.g., approximately 15 degrees at the sharpest point,which may increase closer to a central axis. In some examples, apex 326may be rounded to prevent injury, but may still be sharp around itsedges. To further reduce insertion force and manufacturing time, thehollow surfaces may be surface machined using, e.g., a 1 mm full radiusmill and, e.g., a 0.25 mm step-over, which may result in the wavysurface (including a plurality of rolling peaks and valleys) along theface of the hollow surface. As further shown in FIGS. 29-36, inclinedsurfaces 123 and 124 may include one or more geometric features, suchas, e.g., serrations (shown in FIG. 30), teeth, tapers, bevels or thelike to further facilitate spearing, cutting, slicing, or impacting ofelongate shank 308 through bone and/or tissue. Inclined surfaces 323 and324 also may be formed with an edge (e.g., a v-edge, beveled edge,chisel edge, convex edge or the like) to facilitate impaction.

Elongate fin 310 also may extend away from head portion 306 toward theleading end 304 of vertebral anchor 300. Elongate fin 310 also mayextend away from the concave surface 320 of the elongate shank 308. Thevertical periphery of elongate fin 310 may be defined by a concavesurface 328. In some examples, the elongate shank 308 and elongate fin310 may be generally orthogonal to one another and may form a generallyt-shaped cross-section. The t-shaped cross-section formed by elongateshank 308 and elongate fin 310 may reduce impaction forces of vertebralanchor 300, and may increase the torsional stability of vertebral anchor300 as compared to anchors having planar cross-sections. At leading end304, elongate fin 310 may include a ramped surface 130 that extendstoward apex 326. Ramped surface 330 may include one or more of thegeometrical features described with reference to inclined surfaces 323and 324. In some examples, a vertical periphery of ramp 130 may bebeveled and/or have a v-shaped cross-section.

Turning now to FIGS. 37-40, a further embodiment of a vertebral anchor400 is depicted. Vertebral anchor 400 may extend from a first, trailingend 402 toward a second, leading end 404, and may include a head portion406, an elongate shank 408, and an elongate fin 428. Vertebral anchor400 may be formed from one or more of the materials used to formvertebral anchor 300 and may be treated with one or more similarcoatings, if desired. Vertebral anchor 400 may be inserted into apatient and impacted through bone of a vertebral body.

The head portion 406 may be disposed at trailing end 402 of vertebralanchor 400 and may have a partially spherical outer periphery. In someexamples, the head portion 406 may be formed by a plurality of sphericalsegments formed by removing one or more spherical caps from thespherical outer periphery of head portion 406. In the embodiments shownin FIGS. 37-40, at least three planar surfaces 411, 413, and 450 maydefine at least a portion of the outer periphery of thepartially-spherical head portion 406. In one example, planar surfaces411 and 413 may be substantially parallel to one another, and may besubstantially orthogonal to planar surface 450. In some examples, planarsurface 450 may define the proximal-most portion of head portion 406 andof vertebral anchor 400. That is, planar surface 450 may define thesurface that is furthest toward trailing end 402 of vertebral anchor400. A recess (e.g., a concave recess) 452 may be disposed within planarsurface 450 such that planar surface 450 may be defined by interruptedhemispherical arc portions, as seen in FIG. 32. A bore 412 may have anopening disposed within recess 452. Bore 412 may extend through headportion 406 and may include one or more features described withreference to bore 312 of vertebral anchor 300. While not shown in FIGS.37-40, it is contemplated that head portion 406 may include otherfeatures described with reference to head portion 306 of vertebralanchor 300, such as, e.g., grooves and/or mating features configured tosecure and position vertebral anchor 400 within an anchor channel of aninsertion device.

Head portion 406 also may include one or more protrusions 460 that mayextend away from the outer periphery of head portion 406. In theexamples shown, protrusions 460 may be formed as spherical caps (e.g.,partial domes), although protrusions 460 may be formed in any othersuitable configuration. In some examples, the base of protrusions 460may include an annular rim 462 that may, e.g., extend radially away fromprotrusions 460. In some examples, head portion 406 may include twoprotrusions 460 that extend in opposite directions. It is contemplatedthat another suitable number of protrusions 460 may be employed inalternative configurations.

Elongate shank 408 may extend away from the head portion 406 toward theleading end 404. In some examples, elongate shank 408 may be planar andmay exhibit a curvature as it extends away from the head portion 406. Insome examples, elongate shank 408 may be curved (e.g., symmetricallycurved) about a longitudinal axis. More specifically, elongate shank 408may exhibit a curvature about a median longitudinal axis. Further, theelongate shank 408 may be curved such that a concave surface 420 and aconvex surface 422 extend from trailing end 402 toward leading end 404.The leading end of the elongate shank 408 may be formed by a pair ofinclined surfaces 423 and 424 that extend from the lateral ends ofelongate shank 408 toward an apex 426. Apex 426 may be disposed on alongitudinal axis of vertebral anchor 400. In some embodiments, apex 426may include a curvilinear periphery. Thus, at leading end 404, elongateshank 408 may be formed to include any of the suitable geometries andfeatures disposed on vertebral anchor 300 to facilitate impaction.

In one example, the lateral sides of elongate shank 408 may include oneor more cutouts 421. For example, each lateral side of elongate shank408 may include two cutouts 421 to form one or more keels 425. The keels425 may generally extend and point in a reverse manner with respect to aremainder of vertebral anchor 400. That is, the end points of the keels425 may be oriented toward the trailing end 402 and not leading end 404.Thus, keels 425 may assist in inhibiting vertebral anchor 400 fromexiting a vertebral body once inserted therein. In the embodiment shownin FIGS. 31-34, each lateral side of elongate shank 408 may include twocutouts 421 and three keels 425, although any other suitable combinationof cutouts and keels may be utilized.

One or more apertures 427 may disposed through the surface of elongateshank 408. Though depicted as through-holes, apertures 427 also mayinclude blind recesses disposed in one or more surfaces of elongateshank 308. Once inserted through the bone of a vertebral body, apertures427 may encourage bony in-growth or on-growth therein, further securingvertebral anchor 400 within a respective vertebral body. In someexamples, apertures 427 may be packed with bone graft or otherbone-growth inducing substances.

Elongate fin 428 also may extend away from head portion 406 toward theleading end 404 of vertebral anchor 400. Elongate fin 428 also mayextend away from the concave surface 3120 of the elongate shank 408. Thevertical periphery of elongate fin 428 may be defined by one or morecutouts 431 and keels 435 in a substantially similar manner as thelateral sides of elongate shank 408. In some examples, the elongateshank 408 and elongate fin 428 may be generally orthogonal to oneanother and may form a generally t-shaped cross-section. The t-shapedcross-section formed by elongate shank 408 and elongate fin 428 mayreduce impaction forces of vertebral anchor 400, and may increase thetorsional stability of vertebral anchor 400 as compared to anchorshaving planar cross-sections. At leading end 404, elongate fin 428 mayinclude a ramped surface 430 that extends toward apex 426. Rampedsurface 430 may include one or more of the geometrical featuresdescribed with reference to inclined surfaces 423 and 424. In someexamples, apertures (not shown but similar to apertures 427) may bedisposed on or through elongate fin 428 to encourage bony in-growth oron-growth therein.

In some examples, vertebral anchors 300 and 400 may facilitate easyinsertion of various vertebral spacers (e.g., stand-alone ACDF and/orALIF spacers) through the use of inline impaction of anchors 300 and 400through the spacer. In some examples, the inline operation may befacilitated through appropriate implant design, instrument design, anddesign of the implant-instrument interface. In some examples, thevarious examples of the present disclosure may permit the use ofstand-alone spacers at the most caudal or most cephalad cervical discspaces (e.g., C5-C6/C6-C7 and C2-C3), and at the caudal lumbar levels(e.g., L5-S1) where angled instruments may pose insertion problems dueto interference with tissue or other anatomy.

Any aspect set forth in any example may be used with any other exampleset forth herein. Every device and apparatus set forth herein may beused in a suitable medical procedure, such as, e.g., a vertebral discreplacement procedure, and may be advanced through any suitable bodylumen, body cavity, or incision.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the disclosed systems andprocesses without departing from the scope of the disclosure. Otherexamples of the disclosure will be apparent to those skilled in the artfrom consideration of the specification and practice of the disclosuredisclosed herein. It is intended that the specification and examples beconsidered as exemplary only.

We claim:
 1. An intervertebral spacer system, comprising: anintervertebral spacer including a spacer and a plate, the plateincluding at least one bore; and a vertebral anchor configured anddimensioned to be received in the at least one bore and including: ahead having a bore adapted to receive a revision tool for removal of thevertebral anchor after implantation into a vertebral body; a curvilinearshank extending from the head; and an elongate fin extending from thehead and along a surface of the elongate shank, the elongate shank andthe elongate fin being disposed perpendicular to each other.
 2. Theintervertebral spacer system of claim 1, wherein the bore of the headincludes an internal threading adapted to be threaded to a threaded tipof the revision tool.
 3. The intervertebral spacer system of claim 2,wherein the head of the vertebral anchor includes a plurality ofcircumferentially spaced notches disposed on an exterior surface of thehead.
 4. The intervertebral spacer system of claim 1, wherein the headof the vertebral anchor includes a plurality of circumferentially spacednotches disposed on an exterior surface of the head.
 5. Theintervertebral spacer system of claim 1, wherein the head includes aplurality of circumferentially spaced flanges to form a generallyT-shape cross-section.
 6. The intervertebral spacer system of claim 5,wherein the flanges are circumferentially disposed around the head todefine a plurality of notches.
 7. The intervertebral spacer system ofclaim 1, wherein the head includes at least one groove running laterallyto a longitudinal axis of the fin.
 8. The intervertebral spacer systemof claim 7, wherein the groove is semi-cylindrical.
 9. Theintervertebral spacer system of claim 1, wherein the elongate shank andthe elongate fin form a t-shaped cross-section.
 10. The intervertebralspacer system of claim 1, wherein a leading end of the elongate shank isformed by two inclined edges that converge laterally inward toward aleading apex.
 11. The intervertebral spacer system of claim 10, whereinthe elongate fin includes a ramp that converges toward the leading apex.12. An intervertebral spacer system, comprising: an intervertebralspacer having a spacer and a plate, the plate including at least onebore configured and dimensioned to receive a vertebral anchor; thevertebral anchor including: a head that is at least partially sphericaland having a bore adapted to receive a revision tool for removal of thevertebral anchor after implantation into a vertebral body; and acurvilinear shank extending from the head; and an insertion instrument,the insertion instrument engaging a portion of the plate of theintervertebral spacer and having at least one channel that aligns withthe at least one bore, the channel configured and dimensioned to receiveand guide the anchor from a first uninstalled position where the anchoris not seated in the at least one bore to a second installed positionwhere the anchor is seated in the bore.
 13. The intervertebral spacersystem of claim 12, wherein the bore of the head includes an internalthreading adapted to be threaded to a threaded tip of the revision tool.14. The intervertebral spacer system of claim 13, wherein the head ofthe vertebral anchor includes a plurality of circumferentially spacednotches disposed on an exterior surface of the head.
 15. Theintervertebral spacer system of claim 12, wherein the head of thevertebral anchor includes a plurality of circumferentially spacednotches disposed on an exterior surface of the head.
 16. Theintervertebral spacer system of claim 12, wherein the head includes aplurality of circumferentially spaced flanges to form a generallyT-shape cross-section.
 17. The intervertebral spacer system of claim 16,wherein the flanges are circumferentially disposed around the head todefine a plurality of notches.
 18. The intervertebral spacer system ofclaim 12, wherein the head includes at least one groove runninglaterally to a longitudinal axis of the fin.
 19. The intervertebralspacer system of claim 18, wherein the groove is semi-cylindrical. 20.The intervertebral spacer system of claim 12, wherein the elongate shankand the elongate fin form a t-shaped cross-section.